Local nurseries (small, medium and large sized ones) replenish their camellias inventories in the Fall or Winter. To determine exactly or more or less when, I suggest you visit the store(s) and ask. For example, I notice that Lowes gets camellia shipments on or after October. Whatever inventory remains, it remains until it is sold. Interestingly, running low or selling out of the inventory does not trigger new deliveries from the wholesalers. Because of that, there is not a japonica (only) buying season. The store will get all the camellia shipments at about the same time, regardless of whether the camellia is a japonica, sasanquas, etc.

Certain local stores may have a large inventory and that inventory may last thru the year. That probably varies from city to city.

A recently planted camellia will not need much fertilizer because the potting mix that comes with the shrubs will likely contain those round fertilizer pellets. The American Camellia Society suggests three applications from March thru September using three types of fertilizers. The 1st application should use a high nitrogen fertilizer; the 2nd application should use a moderate nitrogen/phosphate fertilizer; the third application should use a high phosphate fertilizer. Or you could add 1/2 cup to 1 cup or cottonseed meal monthly between March and September (do not feed if the temperatures are warm, say, above 90). You can get specific suggestions for CA from the Napa Valley Chapter of the American Camellia Society; see the link below. Most Miracle Gro formulations are not good fertilizers for camellias as they are too high on nitrogen. A slow-release general-purpose (chemical or organic) fertilizer will do better.

Cottonseed Meal can be purchased in organic minded plant nurseries stores and in small-to-medium size local plant nurseries. The big stores rarely carry it. The Napa Valley Chapter of the ACS might be able to recommend places to get cottonseed meal.

There are many commercial camellia/azalea potting mixes sold that you could use. Or could make your own. See the following posts:
http://forums.gardenweb.com/forums/load/camellia/msg0122484619225.html
http://forums.gardenweb.com/forums/load/camellia/msg1011172231762.html?1

You could fertilize monthly with cottonseed meal during the growing season or apply half the amount of your Miracle Gro every two weeks. From October through February, apply a general purpose 2-10-10 fertilizer.

Luis

Here is a link that might be useful: Napa Valley Camellia Society

Louis is very knowledgeable about what he said. What does acr stand for? I can guess Azalea, camelia ? But please let us know. You said you were gonna grow the camellias in an atrium is this like a real inside atrium? Because if you want to get them acclimated they need to be outside. If you are in California you may locate an actual nursery which would have a better assortment or variety of camellias. Since some bloom earlier than others some nurseries would get in the sansanquas first then start with the japonicas. sometimes it is what is blooming is what is selling. There is a Nucio's nursery somewhere in California but I don't know the location. There are many post on this forum and ma ny people have raved about They are hybridizers and sellers of many different varieties. Some grow better in different locations so do some more research. You may decide you like a special flower color or shape There are only 3 basic colors white ,pink and red but the number of combinations of these 3 colors are endless then the different shapes singles , doubles, formal etc etc. I know I am being long winded. you said you were planting for shade. I too when I first planted my camellias about 5 years past had very little shade. So I planted camellias and I planted trees. Some trees grow faster than other. I wanted pines. I wanted quick growth. The pines have not done well. But I also kept the mulch heavy made sure I watered regularly and I also planted redbud trees they did great and will grow much faster then the camellias so will give a little shade until the pines take off. Hope this helped good luck.
James In Florida

Good morning, James. I assumed that acr = azalea, camellia, rhododendron

Cottonseed meal can also be found at any feed and seed type of store. It is often used to beef up cattle feed, pardon the pun.

Don't be tempted to use a planting mix of any kind unless it is specifically labeled for container growing. Most products that are called a 'planting mix' are intended to be used in-ground, or as an amendment for outdoor planting. They are utterly unsuitable for use as a container medium.

Your goal will be to find a medium that is very coarse textured so that it drains rapidly and provides superior oxygen access to the roots. You can build your own mix, but I've found that the best bagged product is made by Fafard. Fafard makes a retail line, but that stuff is too fine textured and doesn't provide the kind of porosity you should be looking for. Their PROFESSIONAL line is perfect; the Heavyweight options, in particular. I've been using the Nursery Mix for many years. It's a top quality potting mix for all kinds of plants, but especially woody material. You won't need to add anything but your fertilizer.

You will most likely have to have your locally owned garden center or nursery (not the big box outlets) special order you the Fafard. That's what I do, and have never had any problem. You won't find it on the retail shelves.

If you want to make your own, you can greatly improve the typical retail potting soil by adding a plentiful portion of conifer bark fines, maybe 60 to 70 percent bark. I am not talking about mini nuggets, but fines. The particles are about the size of my (female) fingernails. You can often find bark fines at the big box stores.

Here is a link that might be useful: Fafard's Nursery Mix